Description:
‘Espresso’ germplasm was developed from 90 collections from southeastern Arkansas, Mississippi, and western Alabama (Table 1). Seed from of each accession was bulked and planted in a 2.02 ha (5 ac) field at the Jamie L. Whitten Plant Materials Center in the spring of 1995 to re-establish prairie habitat at the center. In the spring of 2004, crown divisions were taken from the original accessions and transplanted into a nine by nine crossing block at the R.R. Foil Plant Science Research Center at Mississippi State University in Starkville, MS. Seed produced the following fall was hand harvested from each plant to produce a composite population for the first screening. Selection for precocious germination (without stratification) and increased velocity of germination was accomplished by collecting seed from the established crossing block. Seed were collected in equal quantities from each mother plant October / November and stored under low humidity (60 + 4% RH) at room temperature (22 + 2oC) until evaluation in January (Holmberg 2007).